Glad to hear you got your problem solved. I wish I was back in this forum sooner to help you. But yeah, if you have a running engine a cracked head or blown head gasket about 95% of the time have issues to start out with ie poor idle, miss fire, ect. If you have a great running engine that has issue after warm up. Then you have a sensor issue. Again, glad to hear you got it solved. GRANTED. I would have gotten the first guy to tear down the engine put a fresh head gasket in it and after that didn't fix it tell him that he is s*** out of luck for a miss diag and you get a free head gasket job out of the deal. But I am a Journey tech at a Ford Dealer.. ha, I like messing with shops like that, F tires plus!